Low-foaming rinsing and washing agents for dish washers

ABSTRACT

LOW-FORMING RINSING AND WASHING COMPOSITIONS ADAPTED FOR DISH WASHERS CONSISTING ESSENTIALLY OF (A) FROM 70% TO 98% BY WEIGHT OF WATER-SOLUBLE POLYVINYL ALCOHOLS HAVING A MOLECULAR WEIGHT OF BETWEEN 1000 AND 4000, AND (B) FROM 2% TO 30% BY WEIGHT OF FOAM-INHIBITING COMPOUNDS SELECTED FROM THE GROUP CONSISTING OF ALIPHATIC ALCOHOLS, ALIPHATIC CARBOXYLIC ACIDS ARE ALKALI METAL SALTS THEREOF, ALIPHATIC CARBOXYLIC ACID AMIDES AND ALIPHATIC AMINES, SAID COMPOUNDS HAVING AT LEAST ONE ALIPHATIC OR ALIPHATIC-CYCLOALIPHATIC RADICAL WITH FROM 8 TO 22 CARBON ATOMS, AS WELL AS AQUEOUS SOLUTIONS CONTAINING SAID LOWFOAMING RINSING AND WASHING COMPOSITONS.

United States Patent 3,629,122 LOW-FOAMING RINSING AND WASHING AGENTSFOR DISH WASHERS Giinter Jakobi, Hilden, Rhineland, Germany, assignor toHenkel & Cie G.m.b.H., Dusseldorf, Germany No Drawing. Filed Feb. 17,1969, Ser. No. 799,932 Claims priority, application Germany, May 4,1968,

P 17 67 384.6 Int. Cl. C11d N00 US. Cl. 252-89 8 Claims ABSTRACT OF THEDISCLOSURE Low-foaming rinsing and washing compositions adapted for dishwashers consisting essentially of (A) from 70% to 98% by weight ofwater-soluble polyvinyl alcohols having a molecular weight of between1000 and 4000, and (B) from 2% to 30% by weight of foam-inhibitingcompounds selected from the group consisting of aliphatic alcohols,aliphatic carboxylic acids and alkali metal salts thereof, aliphaticcarboxylic acid amides and aliphatic amines, said compounds having atleast one aliphatic or aliphatic-cycloaliphatic radical with from 8 to2.2 carbon atoms, as well as aqueous solutions containing saidlowfoaming rinsing and washing compositions.

THE PRIOR ART In an increasing measure, mechanical washing methods arebeing employed to wash china, glass, porcelain, ceramic, metal andsynthetic articles. Detergents containing specific surface-activecompounds are generally utilized. These detergents should be low foamingso that they do not affect the function of the Washing apparatus. A foamformation of too large a volume, caused and increased by the vigorousmotion of the bath in the machine, leads to considerable trouble, as thefoam mass decreases the mechanical efiect of the liquid sprayed onto thearticles to be cleaned, and furthermore may cause the bath in themachine to run over.

Recently, developments in washing apparatus have been directed towardfurther increasing the intensity of the liquor motion as well as thewater volume cycled per minute, and in this way to further improve themechanical cleansing effect. As a result of such developments, it wasfound that conventional washing agents, such as higher molecular weightsulfates or sulfonates, caused too much foam. For this reason, inpractice, nonionic surface-active agents such as ethylene oxide additionproducts to alkylphenols or polypropylene glycols, have been preferred.These products, as well, were found to have a relatively high foamingtendency in the ranges of concentration required for satisfactorywetting and cleansing effect when used in the modern dish washingmachines.

It has also been suggested to utilize combinations of effective wettingagents of the known type of ethylene oxide addition products, withfoam-inhibiting agents, such as ethylene oxide-propylene oxide mixedadducts with fatty alcohols or alkylphenols. However, such combinationsrequire relatively large additions of the foam inhibitors in order todecrease, to a reasonable extent, the tendency of the combination tofoam.

A further considerable disadvantage of the named alkylene oxide additionproducts is that they are not biologically decomposed to a sufficientextent. For this reason, they often play a part in the formation of foamon sluices, dams and overflows. Furthermore, such products oftenexhibit, even in small amounts of only a few mg./ 1., a distincttoxicity toward fish and other water organisms.

Patented Dec. 21, 1971 Thus, they can represent a considerable andundesired burden on waste waters and their treatment.

In my copending US. patent application S.N. 799,933, filed concurrentlyherewith, I have described and claimed highly effective and extremelylow-foaming combinations of detergents adapted to dish washers which,thanks to their biological harmlessness, do not cause any waste waterproblems. These washing and cleansing compositions are characterized bya content of:

(A) 70% to 98% by weight of water-soluble polyvinylalcohols havingmolecular weights of from 1000' to 4000, and

(B) 2% to 30% by weight of interface active compounds containingpolyoxypropylene radicals and/ or polyoxybutylene radicals with 2 tooxypropylene or oxybutylene units and preferably a further content ofoxyethylene radicals or polyoxyethylene radicals, where the portion ofoxypropylene or oxybutylene units in the total number of the oxyalkyleneunits amounts to at least 30% by mol.

OBJECTS OF THE INVENTION An object of the invention is the obtention ofhighly effective and extremely low-foaming dish and general purposedetergent combinations for dish washers which do not cause any wastewater problems due to their biological harmlessness.

A further object is the obtention of low-foaming rinsing and washingcompositions adapted for dish washers consisting essentially of (A) from70% to 98% by weight of water-soluble polyvinyl alcohols having amolecular weight of between 1000 and 4000, and (B) from 2% to 30% byweight of foam inhibiting compounds selected from the group consistingof compounds of the formula wherein R is a member having from 8 to 22carbon atoms selected from the group consisting of alkyl, alkenyl,alkadienyl, hydroxyalkenyl and alkylcycloalkyl; R is an alkyl havingfrom l8 to 22 carbon atoms; R; and R are members selected from the groupconsisting of hydrogen and lower alkyl; and Me is an alkali metal.

Another object of the invention is the obtention of aqueous solutions ofthe above low-foaming rinsing and washing compositions.

A yet further object of the invention is the development of a method ofwashing and rinsing solid articles which comprises forcefully contactingsaid solid articles with water containing from 0.01 to 0.5 gram perliter of the above low-foaming rinsing and washing compositions.

These and other objects of the invention will become more apparent asthe description thereof proceeds.

DESCRIPTION OF THE INVENTION Accordingly, the present invention relatesto lowfoaming rinsing and washing compositions adapted for dish washersbased on polyvinylalcohol and foam-suppressing agents, which isdistinguished by a good compatibility with waste waters and harmlessnessagainst fish and other water organisms.

In particular, these compositions are characterized by a content of (A)from 70% to 98% by weight of watersoluble polyvinylalcohols having amolecular weight of between 1000 and 4000, and (B) from 2% to 30% byweight of foam-inhibiting compounds selected from the group consistingof aliphatic alcohols, aliphatic carboxylic acids and alkali metal saltsthereof, aliphatic carboxylic acid amides and aliphatic amines, saidcompounds having at least one aliphatic or aliphatic-cycloaliphaticradical with from 8 to 22 carbon atoms.

The claimed combination is extraordinarily low foaming even underextreme application conditions, both in household dish washers as wellas in commercial dish washers. As a result of the high content ofpolyvinylalcohol, the compositions of the invention possess an excellentwetting effect with respect to hard surfaces such as porcelain.synthetics or metals. The combinations of the invention are particularlysuitable as low-foaming, clear rinsing agents for dishes and silverwareof all kinds, possibly with a preceding alkaline pre-washing phase, aswell as for washing and clear rinsing of alkaline-sensitive glasswaresuch as drinking glasses and other glassware. An exceptional run off ofthe rinsing water is obtained, resulting in shining, spot-free articles.

The special advantage of the combinations of the invention with respectto known low-foaming rinsing agents is that the requirement fornon-toxicity with respect to fish and other water organisms is met to asatisfactory degree. Although polyvinylalcohol used as the component Ais only slightly biologically decomposed, it can yet be considered asphysiologically harmless since it does not exhibit any toxic properties,whatsoever, toward those organisms which live in water.

Generally, the biological decomposition of the foam inhibitors of type Bis relatively good. Due to the fact that in practice the portion ofcomponent B of the mix- I ture is always relatively small, no disturbingburdens on the waste water are to be anticipated, even in cases wherethe biological decomposability is less due to the use of branched chainradicals or the like.

The water-soluble polyvinylalcohols having a molecular weight of between1000 and 4000 used as component A are known products and are used in thetrade. They can be obtained, for instance, by means of hydrolysis ofpolyvinyl acetates of the corresponding degree of polymerization. Withinthe framework of this invention such watersoluble polyvinylalcohols arepreferred which have a hydrolysis degree of 85% to 90% and havemolecular weights of approximately 1000 to 3000.

As compounds of group B, are, above all, saturated or unsaturated fattyalcohols with 10 to 18 carbon atoms. Particularly useful are compoundsof the formula R-OH wherein R is a member having 8 to 22 carbon atomsselected from the group consisting of alkyl, alkenyl, alkadienyl,hydroxyalkenyl and alkylcycloalkyl. Employed in practice are above allmixtures of such fatty alcohols as are obtained from natural fats andoils. Examples for suitable fatty alcohols are dodecyl alcohol,hexadecyl alcohol, tallow alcohol mixtures of the chain length C to Ccoconut fatty alcohol mixtures of the chain length C to C and the like.In lieu of the natural fatty alcohols, alcohols of a corresponding chainlength can be employed as well which are obtained through syntheticmethods, as, or example, according to the Ziegler method. Furthermore,branched chain alcohols with up to 22 carbon atoms can be utilized ascan be obtained through the oxo-synthesis or through the Guerbetreaction.

Other suitable compounds of group B are fatty acids with a chain lengthof C to C Particularly useful are compounds of the formula RCOOH andR'COOMe wherein R is a member having 8 to 2.. carbon atoms selected fromthe group consisting of alkyl, alkenyl, alkadienyl, hydroxalkenyl andalkylcycloalkyl; R is an alkyl having from 18 to 22 carbon atoms; and Meis an alkali metal. Here too, such fatty acids or fatty acid mixturesare preferred which have been obtained from natural fats and oils as,for instance, from fatty acid mixtures obtained from coconut fats of thechain length C to C or C to C oleic acid, behenic acid as well aspreliminary faction fatty acids containing larger amounts of fatty acidsof the chain length C to C Fatty acids containing more than 18 carbonatoms can be employed in form of their alkali metal salts as well.

Finally, fatty acid amides or fatty amines of the chain length C to Ccome also into consideration as foam inhibitors such as, for instance,tallow fatty acid-N,N- diethylamide, dodecylamine, the tallow aminemixture prepared from tallow fatty acids of the chain length C to C13,Ctc.

The individual components in the low-foaming rinsing agents of theinvention amount to approximately to 98% by weight of component A and 2%to 30% by weight of component B. In practice it was, in particular, thatmixtures from to by weight of component A and 5% to 15% by weight ofcomponent B are particularly suitable.

When the mixtures are used for the washing of dishes, particularly ofdrinking glasses, concentrations of approximately 0.05 to 0.5 gm./liter,preferably 0.1 to 0.4 gm./ liter in the cleaning fluid are required. Ifemployed as rinsing agent subsequent to an alkaline washing phase,approximately 0.01 to 0.25 gm./liter, preferably 0.02 to 0.1 gm./literare used. To a certain degree the concentrations are dependent upon thehardness of the water and the type of dishes. When washing or rinsing,utilizing hard and salty waters, or with plastic dishes, greater amountsof the rinsing agents are required.

Usefully, the compositions of the invention are prepared in the form ofaqueous concentrates with a content of approximately 10% to 30% byweight of mixtures of components A and B. By variation of the amount ofthe components, the concentrates can be adjusted in such way that theypossess a good temperature stability and do not tend to precipitate orseparate into layers. Usefully, the concentrates are added into thewashing and rinsing solution in the dish washing machines by means of anautomatic dosing device as is common for such purposes.

The following specific embodiments of the invention are illustrativethereof. It is obvious, however, that other expedients may be employedand the specific embodiments are not to be deemed limitative in anymanner.

EXAMPLES The foam behavior of different cleansing and rinsing admixtureswas examined for comparison purposes in a special foam examinationapparatus. The following table exhibits the extremely good foam behaviorof the compositions of the invention.

The foam apparatus, as used, was constructed in similar manner as amodern dishwasher operating according to the jet spray system. By meansof a pump about liters of water per minute were rotated and sprayed intothe metering chamber by means of a rotating spray-arm provided withnozzles. Foam heads from 0 to 280 mm. may be measured in reproduciblemanner, whereas larger foam volumes can no longer be measuredaccurately, and, therefore, they are indicated in the table as 280. Theliquor temperature during the tests was 50 C., the hardness of the waterused was 16 dH and the duration of the foam test lasted 5 minutes. Thereading of the foam height was done immediately after the machine cameto a standstill and 30 seconds after the machine had come to a stop.

The foam apparatus is described in Fette, Seifen, Anstrichmittel." 66I964], page 529.

The letters A and B in the following table represent the components inaccordance with the preceding.

TABLE Foam height in mm.

30 sec.

Conc. On after Example Composition of mixture gm./liter standstillstandstill 1o A. Polyvinylalcohol (viscosity of a 4% solution at 20 0.,3 cp., 0.12 280 280 hydrolysis degree: 88%).

1b {1L Polyvinyl alcohol (corresponding to la) 0. 12 15 B. Dodecylalcohol 0.009

, {A Polyvinylalcohol (corresponding to la) 0.12 20 0 B.Hexadecylalcohol- 0.009

3 g A. Polyvinylalcohol (corresponding to la) 0.12 25 B. Dodecylamine...0.02

4 A. Polyvinylalcohol (corresponding to la) 0.12 1o 0 '18. Sodiumbehenate 0.009

5 A. Polyvinylalcohol (corresponding to la) 0.12 0

"""""" "t B. Tallow fatty acidN,N-diethylamide.. 0.009

EXAMPLE 6 A liquid rinsing agent suitable for commercial dish washershad the following composition:

Percent Polyvinylalcohol (viscosity of a 4% solution at 20 C., 3 cp.,hydrolysis degree: 88%) 20.0 Dodecyl alcohol 0.7 Water 79.3

At application temperatures of between 50 C. and 90 C., the productdeveloped practically no foam. Subsequent to the alkaline main washingof the dishes, the above aqueous concentrate was dosed into the rinsingwater in concentrations of 0.4 to 0.6 gm./liter. Spot-free, shiningdishes were obtained.

EXAMPLE 7 An extremely low-foaming detergent for household dish washershad the following composition:

Percent Polyvinylalcohol (viscosity of a 4% solution at 20 C., cp.,hydrolysis degree: 86%) 10.0 Sodium behenate 0.6

Water 89.4

At application concentrations of 0.5 to 1.5 gm./liter, anunobjectionable cleaning and clear drying eifect was obtained.

The preceding specific embodiments are illustrative of the practice ofthe invention. It is obvious, however, that other expedients known tothose skilled in the art may be employed without departing from thespirit of the invention.

I claim:

1. Low-foaming rinsing and washing compositions adapted for dish washersconsisting essentially of (A) from 70% to 98% by weight of water-solublepolyvinyl alcohols obtained by hydrolysis of polyvinyl acetates, havinga hydrolysis degree of between 85% and 90% and having a molecular weightof between 1000 and 4000, and (B) from 2% to 30% by weight offoaminhibiting compounds selected from the group consisting of compoundsof the formula wherein R is a member having from 8 to 22 carbon atomsselected from the group consisting of alkyl, alkenyl, alkadienyl,hydroxyalkenyl and alkylcycloalkyl; R is an alkyl having from 18 to 22carbon atoms; R and R are members selected from the group consisting ofhydrogen and lower alkyl; and Me is an alkali metal.

2. The low-foaming rinsing and washing compositions of claim 1 whereinsaid water-soluble polyvinyl-alcohols of component A arepolyvinyl-alcohols having a molecular weight of between 1000 and 3000.

3. The low-foaming rinsing and washing composition of claim 1 whereinsaid component B is an alcohol having from 10 to 18 carbon atoms andhaving the formula wherein R is a member selected from the groupconsisting of alkyl, alkenyl, alkadienyl, hydroxyalkenyl, and mixturesthereof.

4. The low-foaming rinsing and washing composition of claim 1 whereinsaid component B is an acid compound selected from the group consistingof fatty acids having from 8 to 22 carbon atoms and alkali metal saltsof fatty acids having from 18 to 22 carbon atoms.

5. The low-foaming rinsing and washing composition of claim 1 whereinsaid component B is a tallow fatty acid-N,N-diethylamide.

6. The low-foaming rinsing and washing compositions of claim 1 whereinsaid component A is present in an amount of from to 98% by weight andsaid component B is present in an amount of from 2% to 15% by weight.

7. Aqueous concentrates containing from 10% to 30% by weight of thelow-foaming rinsing and washing compositions of claim 1.

8. The method of Washing and rinsing solid articles which comprisesforcefully contacting said solid articles with water containing from0.01 to 0.5 gram per liter of the low-foaming rinsing and washingcompositions of claim 1.

References Cited UNITED STATES PATENTS 2,854,417 9/1958 Edwards et a1.252-321 2,954,347 9/1960 St. John et a1 25232l 3,235,505 2/1966 Tuvell252-89 POLY 3,254,028 5/1966 Wixon 25289 POLY DIG OTHER REFERENCES Biehnet al.: Polyvinyl Alcohol as an Emulsifying Agent, Industrial and Eng.Chem., August 1948, pp. 1449-1453.

Ross: Chem. Anti-Foaming Agents, May 1949, Chem. Industries, pp.757-759.

Rose: Cond. Chem. Dict., 6th ed., 1960, p. 1098, Reinhold Publ. Co.

LEON D. ROSDOL, Primary Examiner W. E. SCHULTZ, Assistant Examiner US.Cl. X.R.

252l08, 152, 321, DIGEST2

